Andrew Waugh quoted in J. R. Smith, Everest: The Man and the Mountain (1999), p. 226.
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Famous Valentine Blacker Quotes
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“Put your trust in God, my boys, and keep your powder dry!”
From the poem "Oliver's Advice" http://books.google.com/books?id=JmEaAQAAIAAJ&dq=%22Oliver%27s+Advice%22+Cromwell&q=%22Oliver%27s+Advice%22+Cromwell#v=snippet&q=%22Oliver's%20Advice%22%20Cromwell&f=false by William Blacker, published under the pseudonym Fitz Stewart in The Dublin University Magazine, December 1834, p. 700. This line by a different Colonel Blacker is paraphrased from an attribution to Oliver Cromwell (hence the poem's title).
Misattributed